As stated in U.S. Pat. No. 4,117,861, which issued Oct. 3, 1978 to the present inventor, it is the usual practice in present-day dental offices to use a number of separate handpieces which are driven at high speeds by compressed air. In many instances, the high speed air driven handpieces also emit a spray of water and air as a coolant.
It is the common practice in the prior art for such handpieces to be supported on individual brackets which, in turn, are mounted on a console adjacent to the dental chair. Compressed air and pressurized water are supplied to the various handpieces in the prior art equipment through individual tubes. The air and water are obtained from the usual mains, and the flow thereof to the console is usually controlled by foot-operated valves.
In the prior art, additional valves are provided at the console so that the flow of the pressurized air and water to the individual handpieces may also be controlled. With such prior art equipment, the dentist causes the air and water to be supplied to the console by actuating his foot-operated valves; and he then causes the air or water, or both, to be supplied to a selected handpiece, by actuating appropriate valves in the console.
The valves in the prior art consoles, in addition to being complex and expensive, are difficult to operate, and they often require both hands of the dentist to control them. The control unit of the present invention, on the other hand, provides an improved pinch valve control system for distributing the pressurized air and water to the various dental handpieces associated with the console, and by which each handpiece is automatically activated, as it is selected by the dentist.
It will also become evident as the present description proceeds that although the pinch valve control system of the present invention is described in conjunction with dental handpieces, it has wider application in the art wherever the flow of fluid through a supply tube is to be controlled.
U.S. Pat. No. 3,755,899 which issued Sep. 4, 1973 to the present inventor describes apparatus in which dental handpieces are supported in individual holders on pivotally mounted arms, and each arm includes a pinch block at one end which pinches a corresponding flexible tube to prevent the flow of fluid to the handpiece when the holder is in its down position; but which permits the flow of fluid through the tube to the selected handpiece when the holder is in its up position. Therefore, in using the apparatus described in the patent, the dentist selects a particular handpiece from its holder, and he then flips the holder to its up position so as to activate the handpiece.
U.S. Pat. No. 4,117,861 discloses a pinch valve dental handpiece console which has certain advantages over the holder described in U.S. Pat. No. 3,755,899 referred to above in that it is less expensive to construct, and in that it operates by the insertion and withdrawal of the handpiece to and from its holder and there is no need for the dentist to flip the holder to its up position.
The control system of the present invention involves a pinch valve dental handpiece console which is similar in some respects to the console described in U.S. Pat. No. 4,117,861. The control system of the invention also includes pinch valve control modules which are respectively coupled to the handpiece holders and which operate in conjunction with the holders to control the operation of each dental handpiece selected by the dentist. In the control system of the present invention one such holder and one such control module are used to hold and control the operation of each dental handpiece.
The primary objective of the control system of the present invention is to:
a. select and activate a particular handpiece simply by the dentist removing it from its corresponding holder, and to deactivate the handpiece by the dentist returning it to its holder; PA1 b. direct the flow of pressurized operating fluids to the selected handpiece; and PA1 c. coordinate and direct to the selected handpiece the coolant water, coolant air and atomization of the coolant water with the coolant air.
In a typical dental office a number of holders/control module sets incorporated in the control system of the present invention are mounted on a usual console stand which may be attached to the dental chair. The console may have the same general configuration, for example, as the console disclosed in U.S. Pat. No. 4,610,630 which issued on Sep. 9, 1986 to the present inventor. The number of holders/control module sets which can be supported on the console stand of the control system of the present invention is theoretically limited only by the supply pressure and flow required for each handpiece.
The control module of the invention is usually, but not exclusively, used to control the flow paths of water and air to a selected handpiece. The control module, per se, has general utility which is not limited to the control system to be described in the following specification. For example, the control module may be used in conjunction with the pinch toggle valve of U.S. Pat. No. 5,097,868 which issued to the present inventor on Mar. 24, 1992, as a water control to flush the dental cuspidor and fill the patient's cup.
In addition, the control module may be used as a water supply pressure-actuated anti-syphon shut-off valve. Such a valve is used to protect the city water supply from contamination due to "suck-back" from the dental treatment unit during periods of negative city water supply pressure. In this application the control module causes the valve to open and supply the dental treatment unit with city water only when adequate water pressure exists, and it serves to shut off the water flow path if the pressure drops below a selected threshold.